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91.
胡国巍 《吉林大学学报(地球科学版)》1994,(1)
早元古代老岭群经历了三期构造变形,分别形成了三个特征各异的构造形迹组合。Ⅰ世代为层理榴皱组合,由斜卧诏皱、轴面片理和韧性剪切变形带组成;Ⅱ和Ⅲ世代为片理相皱组合,分别由各种位态的片理诏皱和轴面招劈理、膝折面理组合。Ⅰ、Ⅱ世代的原始构造线方位均为近南北向,为近共轴叠加,但固Ⅲ世代构造的改造,现今多变位为北东东向。Ⅰ世代构造形迹组合的特征显示老岭群的早期构造环境具有构造层次较深、以近水平韧性剪切变形作用为主导的特点。 相似文献
92.
吉南早元古代集安群构造解析 总被引:1,自引:0,他引:1
早元古代集安群经历了三期构造变形,分别形成了三个特征各异的构造形迹组合。Ⅰ世代为层理褶皱组合,由平卧褶皱、轴面片理和韧性剪切变形带组成;Ⅱ和Ⅲ世代为片理褶皱组合,分别由各种位态的片理褶皱和轴面褶劈理、膝折面理组成;Ⅰ、Ⅱ世代的原始构造线方位均为近南北向,为近共轴叠加,但因Ⅲ世代构造的强烈改造,现今多变位为东西向。Ⅰ世代构造形迹组合的特征显示集安群的早期构造环境具有构造层次较深、以近水平韧性剪切变形作用为主导的特点。 相似文献
93.
Abstract Whether there existed the Songpan-Garzê massif is a controversial problem. This paper expounds and proves that the old basement of the massif is represented by the pre-Sinian granitic rock series. This massif and the South Qinling fold belt might both be a part of the old Yangtze platform. Rifting generated by the Caledonian orogeny in the terminal Early Palaeozoic caused the massif to be disintegrated from the northwestern part of the Yangtze platform. This disintegration, however, was not thorough, and the rift troughs were later gradually closed and filled up. The Emei taphrogeny that was initiated in the Early Permian Maokou'an Stage involved a second disintegration of this massif from the Yangtze platform. The rift line largely goes along the Muli-Pingwu line. This rifting belongs to synchronous extensional rifting at peripheries of the Yangtze platform and in its interior, showing that the posterior, lateral and interior extension resulting from rapid northward shift of the Yangtze platform led to isolation of this massif together with South Qinling from their adjacent areas. During the Ladinian Stage, the Songpan-Garzê massif and southern Qinling sank strongly en masse. This subsidence continued till the end of the Late Triassic when the late Indosinian movement caused the sea trough to be closed and Songpan-Garzê and southern Qinling to be folded and uplifted and become mountains. 相似文献
94.
采用CEOF(复经验正交函数)对黄河中下游地区15个代表站点近500年来的旱涝等级指数分析结果表明,历史时期本地区的旱涝分布特点可用三种分布型表征:平均型、东西反相型和南北反相型,对上述三种旱涝分布型的时间振幅,应用Mann-Kendall方法进行突变检验,可以发现平均型和东西反相型近500年来发生旱涝突变,而南北反相型则相对比较稳定。 相似文献
95.
Decompressional coronas and symplectites in granulites of the Musgrave Complex, central Australia 总被引:2,自引:0,他引:2
Abstract In granulite facies metapelitic rocks in the Musgrave Complex, central Australia, reaction between S1 garnet and sillimanite involves the development in S2 of both garnet + cordierite + hercynitic spinel + biotite and hercynitic spinel + cordierite + sillimanite + biotite. The S2 assemblages occur either in coronas and symplectites, mainly around garnet, or, in rocks in which S2 is more strongly developed, as recrystallized assemblages. Ignoring the presence of biotite and ilmenite, the mineral textures can be accounted for qualitatively by a consideration of the model system FeO-MgO-Al2 O3 -SiO2 (FMAS); the textural relationships accord with decompression accompanying the change from S1 to S2. However, since biotite and ilmenite are involved in the assemblages, the parageneses are better accounted for in terms of equilibria in the expanded model system K2 O-FeO-MgO-Al2 O3 -SiO2 -H2 -TiO2 -Fe2 O3 (KFMASHTO), i.e. AFM + TiO2 + Fe2 O3 . The coronas reflect the tectonic unroofing of at least part of the Musgrave Complex from peak S1 conditions of about 8 kbar to S2 conditions of about 4 kbar. 相似文献
96.
本文以新疆阿尔泰某多金属矿区为例,对岩矿光谱特征、不同岩性段岩石化学特征、细分红外光谱遥感图象色调异常进行研究并通过野外验证后提出:Fe3+除在900nm 处具有强吸收特征外,在2150nm 附近有一个反射峰特征;细分红外光谱遥感图象色调异常的形成机理是与 Fe3+的2150nm 附近的反射峰特征有关的综合光谱信息的反映。 相似文献
97.
地理系统与地理信息系统 总被引:84,自引:7,他引:84
人类认识自己住居的星球是漫长的,然而是加速度的。学科的分化和交叉是多层次的。统一地理学一再遭受过冲击,但它的合理的内核——地理综合体是客观存在的。地图和遥感作为信息载体证实了这一观点。地理系统的概念反映当代科学技术进步和社会需求;而地理信息系统为地理学发挥区域性与综合性的优势提供了一种现代化的高技术手段。 相似文献
98.
99.
100.
Silvia Trini Castelli Enrico Ferrero Dominico Anfossi 《Boundary-Layer Meteorology》2001,100(3):405-419
In this work, three turbulence closure models, Mellor andYamada level 2.5, E - l and E - implemented in a circulation model, are compared in neutral condition over complex terrain. They are firstly applied to a one-dimensional case on flat terrain and then to a schematic two-dimensional valley. The simulation results, in terms of wind field and turbulent kinetic energy, are tested against measurements from a wind-tunnel experiment. The empirical constants defining the characteristic length scales of the closures are modified based on turbulence parameters estimated in the experiment. The formulation of the diffusion coefficients is analysed to explain the differences among the various closures in the simulation results. Regarding the mean flow, both on flat and complex terrain, all the closures yield satisfactory results. Concerning the turbulent kinetic energy, the best results are obtained by E - l and E - closures. 相似文献